Tractor bridge crane



April 21, 1925. I 1,534,020

1 H. E. BALDWIN TRACTOR BRIDGE CRANE Filed Nov. 8, 1924 2 Shets-Sheet 1 Aprifi 21, 1925. 1,534,020

H. E. BALDWIN TRACTOR BRIDGE CRANE Filed Nov. 8, 1924 2 sh t -sheet 2 F ff LJLILJLJLJLILJLJULJLILIULJUULILJLJLJLJUJ 7 fiuvawvow 6 Hwam E Baldwin.

Attorqgy,

Patented Apr, 21, 1925.

UNITED STATES ?ATENT @FFECE.

HIRAM E. LBJ'sLIDW'IN,v DE CLEVELAND, OHIO, AS-SIGHO'R- TO THE BROWN HOISTING MACHINERY COMPANY, 01 CLEVELAND, OHIO, AN INCORPORATED COMPANY.

rnnccron BRIDGE CRANE.

Application filed November 8, 1924:. Serial No. 748,664.

7 acters in each case.

My invention relates to traveling bridgecranes, such as are used in the ore and coal handling trades to store'materia'l when unloaded from boats, and, to reclaim. it and load it into cars for reshipment. Itparticularly relates to means for propelling'bridgecranes along their supporting track-rails.

On account of the large storage areas which cranes of this type are required to serve, and, of the quantity of material to be stored, (ore is sometimes piled seventy feet high) bridge-cranes are of great length and their supports, known as pier and shear legs, tower to a great heightas much as ninety feet in some instances. The span of these cranes sometimes exceeds a distance of fourhundred feet, which, together with long cantilever projections of upwards of two hundred feet, a trolley travel of nearly one thousand feet can be had; It will be quite evident that these modern bridge-cranes are of enormous size and tremendous weight. These colossal structures weigh as much as twelve hundred tons and sustain and carry moving loads of one-lnmdred' and eighty thousand pounds, comprising a man trolley (so-called), a grab bucket and the load of material to be carried. Huge multi-wheeled trucks two under each supportingleg are required for the typeof bridge shown in the drawings, to support the bridge-crane and to move it along its track-ways.

In some instances these bulky and unwieldy cranes are propelled along their trackways by driving the supporting truck-wheels through trains of gears from the source of power on the structure. In other instances they are propelled by means of bull-pinions which are driven by the source of power through trains of gears and which engage racks that are located on the foundation adjacent to and parallel with the traclcrails.

In the former mentioned case the source of power, usually an electric motor, sometimes is located on the bridge proper with the requisite shafting, equipped with the proper gears, leading therefrom to the gears on the driving-wheel axles; the source of power sometimes is located on the pier and shear truck-sills, in which case there are two propelling unitsone' on each sillc'oupl"ed' up by the proper wiring to propel the pier and shear truck-wheels simultaneously and at the same rate. In a rack and bull-pinion arrangement the propelling units are generally likewise located on the pier and shear sills and act to drive the bull-pinions directly and thereby propel the bridge forwardly and backwardly upon its truck wheels. I

Bridge-cranes when propelled through the medium of their supporting truck-wheels are usually equiped with railclamps (either automatic or hand-operated) to help the primary braking mechanism to hold them against skidding movement along their their tracks during wind storms. When rack and bull pinion units are employed as the propelling means, no ancillary holding devices are required to prevent any skidding movement of the bridge-cranes, as the bullpinions when sufficiently locked against rotation will prevent any such movement.

My invention has to do with the so-called rack-drive bridge-cranes. It was evolved to meet important and imperative trad-e demands and coi'idition's, which require that bridge-cranes of the kind in question be fabricated and erected in acomparatively short time, as for instance, in the case of a crane suddenly demolished by a wind storm; a new crane must be fabricated and installed in great haste.

The principal advantages that my invention affords over the present time of rackdrive units are recited and described hereinafter.

It is practically impossible to standardize the massive structures under consideration because of the d'itl-erent problems and conditions presented by each customer. Every crane becomes special and considerable time is consumed in the engin-eeriiig department to produce tl'ie drawings for special parts like the propelling units. The making of the patterns, producing and d elivering the steel-castings from such. patterns, as

= bridge-proper during erection, then to assemble the bridgespan. After the bridge parts have been duly riveted and bolted the shear is erected and joined to the bridge. the

cantilevers are then built outwardly from the pier and shear supports.

It will be evident that when the propelling 'units are built in or upon the pier-leg and shear-leg sills, erection of the bridgecrane will be materially delayed and cannot 3 proceed expeditiouslyuntil all the mechanical parts have been finished and fitted to their respective places on the structural work. 7

A principal purpose of my invention therefore, is to facilitate and expedite the erection of bridge-cranes, and I attain this object by my improved and simplified method ofprocedure, which consists in providing independent propelling units or tractors for moving said bridge-cranes and arranging the supports of said cranes so that said tractors may at once be placed into position after the erection of said cranes.

Aside from the fact that erection may be commenced as soon as the structural parts 7 are ready, an important advantage gained by my improved method of erection is, that the propelling gear can be fabricated and assembled in the shop where facilities and experience are available to insure a perfect mechanical job, and the tractors can be inserted in their designed places any time after the erection of the pier and shear legs without further finish or fitting in the field.

As will be manifest from subsequent descriptions herein, among the additional ad-' vantages of my novel correlation of bridge and tractor'as separate units, is the assurance of thereby obtaining a better and more constant pitch line engagement between the teeth of the rack and the bull-pinion, also, by reason of the fact that, different from the tractor feature of other types of crane, the tractor in my invention is supported and moves upon the tracks rails of the crane instead of being carried by the leg-members, the weight of material and consequent structural strains of the main apparatus, are thereby correspondingly reduced.

Further, by dis-associating the bull-pinion tractor as an integral and fixed part of the crane, and giving it an entirely separate, though coactive unitary character. I accomplish that, like tires on wheels of the automobile, for instance, the tractors may be carried as spare parts, so that in the event of an accidental disablement of the bull-pinion tractor in use, the crane itself will not be put out of commission for any extended time while the broken tractor is being removed and a new one is accurately fitted and fixedly attached in its place.

In 'vieW of the considerable capital that is always directly or indirectly held idle by unanticipated interruptions in the worlc ing of plants of the kind in question, this removable and readily replaceable quality of my improvement, should prove of great value as compared with the type of bridge cranes wherein the tractor is integrally fixed in its operative position.

The character of the invention, upon reference to the drawings and, when considered in conjunction with the specifications, will be readily understood.

In the said drawings Figure I is an isometric view of a bridge-crane and propelling tractors, the said crane having its sup-- porting legs adapted to receive the said tractors between their pairs of trucks; Figure II, is an enlarged side view of one of the tractors showing its relation to a le which only a part is shown, and Figure III is a plan view of the tractor shown in Figure II.

Referring to the drawings 1 is a bridgecrane which is supported by pier-legs 2 and shear-legs 3. The said legs are mounted, respectively, on wheeled-trucks 4, 4t and 5, 5 and are adapted to travel onthe t'ack rails 6, 6, 6, 6.

Between andmidway of the pairs of rails 6, 6 and 6, G and parallel therewith are racks 7, 7 which are secured to the track foundation (not shown).

Because of the dilleren'ce in the contours and constructions of the pier-legs andshearlogs, the sills connecting the leg members must ary, to meet different conditions. However, the sills have a close similarity,

and in order to avoid seeming duplication,

I accordingly have chosen to describe only the details ot. the shear-legsill and the rela tion of the tractor to that sill and the shear rack and track.

A truss-sill 8 connects the lower ends of the shear-leg members 3, 3; it is located above the track rails at a height to provide enough space for a propelling unit or truetor 9 to be inserted between its lowest horizontalmember 8 and the truck-rails 6, ,6. Struts 10, 10, that extend inwardly a short distance from the bottom of the shear-leg members 3*, 3, are supported from the sill 8 at their inner ends by the hangers 11, 1.1,

inc

' two pairs of trucks 12',

together serve to stop orlimit any movement of the intervening bull-pinion tractors ashereinafter will appear.

The bull-pinion tract-or 9 is made up of 12 and a body or rectangular connecting frame- 13. The trucks 12, 12 are of the same track-gageas the bridge-crane trucks and tavel on the same tracks. The lengtl'r of the frame 13 is slightly less than the distance between the inner ends of the struts 1'0 and the latter distance will of course be such as to freely admit between the ends a t'actor for the bull-pinions of suitable dimensions for all the purposes designed. The frame 1 3 is-provided nee its ends with depending members 1%, ll which" are-locateel centrally thereof on the median line, in plan, and which are provided with socxcts to engage ball-like protuberances 15 15 on the upper sides of the frames of the trucks 12,12. The purpose of the ball and socket connections is to provide universal joints so that the trucks 12, 12 can adjust themselves to track irregularities without materially disturbing the balance or equilibrium of the tractor frame'. Extending laterally from the sidesof the frame 13 and at the central portion thereof are sub-frames 13 13. These sub-flames carry the gear driving motors 16, 1'6 and the worm-and-gear housings 17, 17. The frame 13 has rectangular opening 1 8- which extends through its entire depthto admit bullpinions 19, 19 and the gearing by which the bull pinions are-actuated. Primary countershafts 20, 20, carrying pinions 21-, 21, extend from the" worm-and-gear housings across the top of the frame 13- and are supported at their outer ends by bearings 22, 22, that are provided on the frame for the purpose. Secondary counter-shafts 23, 23', are located between the shafts 20 and the ends of the frame 13; they extend across the top of the tractor-fiame and are supported at their ends by bearings 24;, 2-1: and 2st, 24. Mounted on the shafts-2, 23 and i n aligmnent with the pinions 21, 21 are spur-gears 25, 25-. The shafts 28, 253 are further provided at their centers with spur-pinions 26, 26,. which are also located on the median line of the frame. Directly below the shafts 23, 2'3 and extending across the bottom of the frame 1 are tertiary counter-shafts 28, 28, which are supported by depending bearings 29-, 29. The bull-pinions .19, 19" arelocated intandem on the shafts 28, 28 midway of the frame 13; they are of suitable size to extend toand mesh with the spur pinions 26, 26 and the 'acl: 7 on the foundation. The frame 13 is furtherprovided at its ends with shelf-like projections 13", 13 that extend from points on the frame that are below the struts. 10, 10, to a short distancebeyond the ends of said struts. It will be observed, upon reference to Figure ll in the drawings, that the space between the tops of the extensions o I3 and: the strut-s16, 10 is s-utheient to ad:- mit and alto-rd seats on the projections for I-beams 13- 13, with enough cleara'uce above suclr members to take care of track: variattions when the bridge-crane lS-1)L()1)Lll';.(l by the tractor. It will be evident that when the I-beam members 13, 3, are removed from the tractor the latter can be skidded sidewise into position between the struts 10-, 10 then lowered onto the track-rails, or, by raising thetractor until its tracl-z-wheel' flangesclear the rails, it can be removed sidewise from its position between the leg-members- The werm-and-motor shafts 80, 30', are pro-- vided with solenoid-brakes 31, 31' and fly-- wheels 32, 32.

While I have chosen to show and describe a tractor with two separate driving units such as motors, claims to a device when so equipped'.. One driving unit per tractor will be sufficient to hold or drive a bridge-crane. A second driving unit is installed as a precautionary measure only, to provide against a possible failure of the mechanism and bull-pinion teeth for a given unit;

A controller 33- for regulating the flow of electric current to the several motors through the cables-34. and 35 for a eration of the tractors is indicated onthe bridge span within easy accessof the operator on the man-trolley (not shown).

After a perusal of the foregoing the operation and the propelling and holding functions of the tractors will be quite apparent and it will further be apparent that the tractor cannot be dislodged from its position within the sill.

Because of the large capacity grab-buclzets carried by the man-trolleys employed on these gigantic bridge-structures, which have a great spread and are carried through the pier and shear supports, and, because of the height of the span, the pier-leg and shearleg members must necessarily be built far enough apart to accommodate those conditions,- consequently the center to center distance of the supporting trucks is as much as sixty feet, which is substantially the length of the sills. It will be evident when the propelling mechanism is of the rack and pinion type and is built upon or into the sill structure as in prevailing types, that because of the unevenness and irregularities in the foundations, track-ways and racks the rack and bull-pinion cannot at all times be in perfect mes-h. To illustrate: V hen the sills spa-n depressions in the rack and trackways, as for example like the chord of an are, they will be fart-her away from the tracks and racks at their center portions, where the bull-pi-nions are mounted, than at their ends which are near the trucks, consequently, the bull%pinions will be lifted out I do not intend tolimit my simultaneous oplit) of an arcuate mesh with the rack, and, conversely, when there is a hump in the rack and track-ways between the trucks, the bullpinions will project farther into the rack out of a true mesh, and, to an extent that will am together the teeth of the rack and bull-pinion with the force exerted at that point by the weight of the bridge-structure above. By utilizing tractor units, as herein described and claimed, as the means for propelling bridge cranes the eonditions,just above recited, will have. no appreciable effect on the mesh of the bull-pinion with the rack, because the center to center distance of the tractor-trueks is less than half the distance between the main or bridge-trucks.

Most bridge-cranes are adapted to skew, because the propelling elements do'not drive the pier and shear truck at a uniform speed. When either end of the bridge is advanced over the other the bridge span has a skewed relation with its pier and shear supports which results in the shear legs tilting inwardly at the top, toward the pier. Now, since the sill is a component and integral member of the shear support, it will likewise be out of plumb, as will also any mechanisms that are attached to it. My method of driving, however, will not be affected by this condition inasmuch as the propelling tractor is a separate and independent unit. It will thus be seen that with my construe tion, propelling units are provided which can be easily positioned between the shear leg-members and also between the pier legmembers of a bridge-crane and which can be easily removed therefrom when occasion requires. The fabrication of the crane i proper and of the propelling units'can proceed separately and independently and the completed tractor time toproduce, can be installed after the bridge-crane has been completely erected.

'lt willalso be seen that the propelling,

units are not rigidly secured tothe bridge crane. One end or theother of each tractor unit merely contacts with the adjacent legmenibcr to propel or hold the crane, and suiiicient clearance is provided between each unit and the sections of the leg-members with which it may contact so that relative movement of the propelling unit and crane legs maytalre place to compensate for variations in track and rack levels, while maintaining a suitable propelling or holding with the legs. 7

Having thus described my said invention as represented in a concrete form or embodiment, what I claim and wish to secure by Letters Patent, is 1- 1. In combination, a bridge-crane having supporting legs mounted on wheeled trucks; parallel track rails forming runways for said trucks; racks along said runways between said rails; bull-pinion tractors, movunits, which require more relation I for said trucks; racks along ably mounted on said rails centrally of the leg-members, in operative relation to said racks; sills, connecting said leg members above the tractors, and stop-members severally extending from the sills to the front and rear of said tractors when in their stated positions on the rails.

2. In combinat on, a supporting legs mounted on wheeled trucks; parallel track rails forming runways for said trucks; racks alongside said runways; bull-pinion tractors,

ofthe leg-members and in mesh with said racks; truss-sills, connecting the leg-members at suitable height above the tractorsto leave a clearance between the lowest horizontal member of the sill and said tractors of not less than the distance the tractors extend below their supporting rails when in normal place thereon, and stop-like members, supported by the sills, at the front and rear of the tractors when in their said normal places.

3. In combination, a bridge-crane having supporting legs mounted on wheeled trucks; parallel track rails forming runways for said trucks; racks along said runways between said rails; bull-pinion tractors, having flanged truck wheels mounted on said track rails between the leg-members and in opcrative engagement with said racks; truss-sills, connecting the leg-members at suitable height above the tractors to permit the tractors to be raised clear of their rails and rack engagement When said tractors are to be re moved from or placed in their normal positions betweensaid leg-members, and stoplike members supported by said sills at the front and rear of said normal positions, substantially as shown and described.

4:. A crane comprising an overhead bridge: supporting legs therefor mounted on wheeled trucks; parallel track ails forming runways for said trucks; racks along said runways between said rails; bull-pinion tractors movably mounted on said runways in operative engagement with sa-idraclcs; truss-sills extending between the leg-members at a suitable height above the bull-pinion tractors to leave suflicient clearance to permitsaid tractors to be raised free of their rails and rack engagement, together with stop-like parts depending from said sills at the front and rear of the spaces occupied by said tractors when in their normal positions on the runways, substantially as shown and described.

5, A'crane comprising an overhead bridge; supporting legs therefor mounted on wheeled trucks; parallel track rails forming runways said runways between said rails; bull-pinion tractors movably mounted on said runways in operative engagement with said racks, and a framebridge-crane having having flanged truck wheels mounted on said track rails centrally work affixed to said leg-members extending above and at the front and rear of the space normally occupied by said tractors when in their normal positions on said rails.

6. Acra-ne comprising an overhead bridge, supporting legs therefor mounted on wheeled trucks; parallel track rails forming runways for said trucks; racks along said run ways between said rails; bull-pinion tractors movably mounted on the runways centrally of the leg-members and in operative engagement with said racks; a framework affixed to said leg-members extending to the front and rear of the space occupied by said tractors when in their normal places on the runways with its lowest horizontal member above the tractors when in such position, at a suitable height to permit the tractors to be raised clear of their rails and racks when they are to be removed from, or placed in, said positions, and, removable means for locking the tractors in their said positions on said runways, substantially as shown and described.

7. A tractor bridge-crane con'iprising an overhead bridge with supporting legs; track rails upon which the legs are movably mounted; racks alongside the rails; bullpinion tractors movably mounted on said rails intermediate of the lower ends of said leg-members in operative relation to said racks; a truss-sill connecting the leg-members and extending downwardly at the front and rear of the spaces occupied by said tractors when in their said positions on said rails with their lower-horizontal member of said sill at a sulficient height above said space to permit the tractors to be raised from said positions until clear of their rails.

8. In combination, a bridge-crane having supporting legs for its overhead bridge mounted on wheeled trucks; parallel track rails forming runways for said trucks; racks along said runways between the rails; bulpinion tractors, having wheeled trucks to which they are jointedly connected, mounted on said rails between said leg-members with their bull-pinion members in operative relation to said racks; truss-sills, connecting said legs above said tractors and extending downwardly at the front and rear ends of said tractors when in their stated position on said rails.

HIRAM E. BALDWIN. Witnesses L. P. Lrrrs, C. S. MALTBIE. 

